We plan to perform RapidTEG upon admission, at 3-hours post-admission, 6-hours post-admission, 12-hours post-admission, 24-hours post-admission, and then daily for 4 additional days. Blood samples (2 mL non-citrated fresh whole blood) will be obtained in addition to standard blood samples for major trauma patients. RapidTEG will be performed using the Thrombelastograph 5000 (Hemoscope Corporation, Niles, IL). Coagulation will be activated by tissue factor. Standard parameters will be obtained using Hemoscope software: TEG-ACT, r-time, K-time, alpha angle, maximum amplitude (mA), and LY30. In addition to RapidTEG, we plan to perform conventional kaolin-activated TEG, prothrombin time (PT), international normalized ratio (INR), activated thromboplastin time (aPTT), and platelet count using standard methods. The time from obtaining the blood sample until the time that the results are made available will also be recorded for all parameters tested. For the RapidTEG, this will include the final results for the test as well as the times that the TEG-ACT, alpha angle, and MA become available by graphical display.